1. Field of the Invention
This invention relates to a broadcast acknowledgement method and system, and particularly, to a broadcast acknowledgement method and system suitable for the purpose of confirming whether or not a commercial program has been broadcast over the radio or televised.
2. Description of the Prior Art
Generally, in sponsored radio, television and CATV broadcasts, many commercial programs are presented. Such commercial programs are, for example, in the case of television broadcasting, televised at a specified time on a specified day on the basis of an agreement, signed by the broadcasting station and sponsor through the advertisement agents, concerning the broadcast time and content.
However, broadcasting of such commercial programs is very expensive and, in the case of television broadcasting, a sponsor must pay a large sum of money to the television broadcast station in charge of such broadcast for only 15 seconds of broadcast. In some cases, errors occur, and a commercial program other than the one intended is broadcast or televised, or the intended program is not broadcast or televised at all due to a mistake at the broadcasting station, signal interference, or broadcasting system down-time.
Thus, whereas a signed agreement may call for program A to be broadcast two times continuously at a specified time, such program may not be broadcast, or programs B and C may be broadcast instead due to a failure of the program editing system at the broadcasting station. In such a case, the specified commercial program is not broadcast in spite of the fact that a high on-air charge is paid, and the sponsor suffers a great deal of monetary damage. Thus, it is necessary for the broadcasting station to compensate the sponsor for the on-air charge as a result of breach of the agreement.
Under usual practice, the broadcast station, the sponsor and the advertisement agent arrange for monitoring the broadcast of commercial programs in each predetermined service area, in order to determine whether or not the commercial programs of concern are broadcast. In that manner, a judgment as to the necessity for compensation can be made. This manual method is lacking in accuracy and speed with which data for confirming the fact of broadcast can be obtained, and also has an inherent disadvantage in that the sponsor and broadcast station experience higher personnel expense and unnecessary inconvenience. For this reason, various methods and systems for automatically confirming the broadcast of commercial programs without the use of monitors have been proposed.
One such method and system involves the insertion of information for confirming the broadcast of commercial program (known as "acknowledgement signals") into the video signal track by superimposition of such an acknowledgement signal on the video signal. The confirming information consists of the sponsor's name, product name, and broadcast time. In such a system, the acknowledgement signals are in digital form, and a sub-carrier signal is inserted into the video signal in accordance with said digital information. Thereby, the commercial film is generated.
The latter method is not desirable because the influence of the sub-carrier signal, inserted in accordance with the digital information, appears on the CRT screen of the television receiver. Namely, CRT "flickers" appear, thus deteriorating the quality of the display image.
A second technique employs a method of inserting a frequency signal sequence in place of the voice signal of the commercial program during a short time .DELTA.t. Commercial program "start" and "end" signals are inserted into the sound track of the commercial film. According to the method, simultaneously, the voice signal at the specified position is removed for the time of .DELTA.t with reference to the "start" signal inserting point, and a desired frequency signal from among the frequencies Sl to Sn of the audible frequency range is inserted in place of the removed voice signal. The inserted frequency signal is detected at the receiving side, and the broadcast of a particular commercial program can be confirmed by the frequency signal sequence.
Thus, by this technique, the frequency signals inserted in each time .DELTA.t are considered as f.sub.1, f.sub.2, the insertion of signal f.sub.1 indicating the data "1", and the insertion of signal f.sub.2 indicating the data "0". These data "1" and "0" are inserted, respectively, as the particular broadcast information. However, this method has the disadvantage that the sound quality of the commercial program is deteriorated, and the television viewers experience inconvenience, since the voice signal of the commercial program is eliminated for the insertion time of .DELTA.t.
By a third existing method, the commercial program broadcast "start" and "end" signals are inserted into the sound track of the commercial film, or into the video signal recording (video track) or perforation part, and at least one particular frequency component, which is included in the commercial voice band frequency appearing in the period from "start" signal detection to "end" signal detection, is detected with a band-pass filter. Thereby, the pattern of the particular frequency signal component is obtained, and thus, the broadcast commercial program can be identified, that is, broadcast of the commercial program can be acknowledged.
This third method also has a disadvantage in that the system becomes large in size and complicated, and accurate identification is difficult since identification is performed as a function of the distribution of the particular frequency signal component. Moreover, in this method, it is impossible to insert the sponsor name, etc.
As described above, the existing methods have various disadvantages, and therefore, have still not been put into practical use. The advent of a method and system which allows insertion of various data, and which automatically and accurately acknowledges the broadcast of a commercial program without deterioration of the sound and image quality of the commercial program, has long been desired.